Krellenstein, M. (April, 2001). What have we learned from evolutionary
psychology?
Marc Krellenstein
Northern Light Technology Cambridge, MA
Emmanuel College Boston, MA
krellenstein@acm.org
ABSTRACT
Evolutionary psychology claims biological inclinations for certain behaviors
(e.g., a desire for more frequent sex and more sexual partners by males as
compared to females), and the origin of these inclinations in natural selection.
Jerry Fodor's recent book, The Mind Doesn't Work that Way (2000), grants the
nativist case for such biological grounding but disputes the presumed certainty
of its origin in natural selection. Nevertheless, there is today a consensus
that at least some of the claims of evolutionary psychology are true, and their
broad appeal suggests that many see them as easy insights into and possible
license for some controversial behaviors. Evolutionary psychologists, on the
other hand, caution that an origin in natural selection implies only an
inclination for certain behaviors, and not that the behaviors will be true of
all people, will lead to happiness or are morally correct. But such cautions can
be as facile as the simplistic positions they are intended to counter. A
biological basis implies tendencies to behaviors that will be pleasurable when
engaged in, and that can be modified to an extent and at a psychic cost that is,
at best, not fully understood. Also, while it is true that naturally selected
behaviors are not necessarily moral, the implications of current evolutionary
psychology cast doubt on any absolute foundation for morality at all, as well as
suggesting limits on our ability to fully understand both ourselves and the
universe around us. However, this does not mean that our (relative) values or
apparent free will are any less real or important for us.
WHAT HAVE WE LEARNED FROM EVOLUTIONARY PSYCHOLOGY?
Evolutionary psychology posits that evolution is responsible not only for
human physiology and anatomy but also for certain human behavioral
characteristics. These characteristics, no less than physical characteristics,
are found to offer a reproductive advantage, resulting in evolutionary selection
of them through selection of the underlying biological (e.g., genetic, hormonal)
basis of those characteristics. One of the most popular and widely accepted
claims of this sort is the evolutionary explanation for the presumed
biologically based fact that men tend to want more sex than women - more
frequent sex, more sexual partners and more casual sex. The claimed reproductive
advantage for this behavior is that a man wanting sex most of the time and with
different people could father a very large number of children as compared to one
who didn't, while such an inclination in women would not produce a comparable
advantage, since women can have at most one child every nine months. Similarly,
a biologically based attraction by men to younger women would result in more
fertile partners and more offspring (an attraction to post-menopausal women
would, at the extreme, be a genetic dead end), while an attraction to younger
men by women would not make much of a difference in pregnancy or survival rates
and hence not be selected for. These biological inclinations do not imply that
women might not also want sex frequently, desire multiple partners or be
attracted by youth, or that any particular woman might not be more so inclined
than any given man, given the range of factors that contribute to such complex
behaviors. Rather, the claim is only that a presumed reproductive advantage
results in a greater biological inclination for these behaviors among men,
suggesting, as seems to be the case, that they are likely to be more pronounced
among men in general.
One of the most notable recent books elaborating on the ideas of
evolutionary psychology is Steven Pinker's How the Mind Works (1997), to which
Jerry Fodor has now offered a characteristically cheeky challenge in The Mind
Doesn't Work That Way (2000). Fodor reminds us that there are two separate
claims in such explanations: a biological basis for certain behaviors - for
nature ('nativism' is Fodor's preferred term) as opposed to nurture - and for
the origin of this biological grounding in evolutionary (reproductive) benefits.
On the first claim, Fodor has, with one-time colleague Noam Chomsky, long been
on the nativist side, and Fodor commends Pinker for his review of the primary
evidence here, observing that it is still the minority viewpoint compared to the
empiricist 'blank slate' view of human nature. The key evidence for the
evolutionary position comes both from animal studies (and the presumed
continuity between animal and human evolution) and various kinds of cultural
data. For sexual differences between the genders that cultural data includes
cultures with males having multiple wives without much in the way of the
reverse; the long-standing presence of pornography aimed at men, but not women;
and the extent of promiscuity in male, but not female homosexual relationships,
suggesting that the natural expression of male sexuality when not compromised by
female sexuality is for more promiscuous behavior (this last is a nice example
of the creative but sometimes tenuous hypothesizing of researchers in this
area).
Pinker also summarizes evidence for the claimed evolutionary explanation
for the biological grounding of these behaviors, but Fodor is much more critical
of this claim. Some of this evidence is little more than speculation on how a
given behavior would enhance survival, though other instances - such as the
relationship among mammals between the size of male genitals and the degree of
promiscuity of the female (more promiscuity is linked to larger genitals = more
sperm = more assurance of paternity) - are closer to the predictive explanations
expected of accepted scientific theories. Overall, though, the data supporting
an evolutionary explanation is more ambiguous and open to other interpretations
than the data supporting biological grounding itself. As has been frequently
observed, explanation by appealing to natural selection is almost too easy - it
is fairly simple to create a story about almost any behavior having at least
some reproductive benefit in some circumstance. We can easily theorize
reproductive advantages of aggression, but also for cooperation; for more
promiscuity among males but also for the tendency of males to form pairs and
care for dependent human children (who need a relatively long time compared to
most animals before they can fend for themselves). Of course, all of these may
be true -- natural selection isn't especially neat, and contrary behaviors may
exist because of what they contribute at one time or another in one's life, or
the way they interact, or as distinct but separately successful reproductive
strategies - but it makes it more difficult to figure out what is and isn't the
result of natural selection.
What could produce such biologically grounded behaviors if evolution is not
the explanation? The alternative explanation is that such behaviors are the
incidental byproduct of other aspects of human development which may themselves
have had (or, for that matter, also did not directly have) an evolutionary
explanation. This is a view closely associated with Stephen Jay Gould (see
Gould, 1997, for example) and it is Fodor's view as well. Fodor spends the last
chapter of his book attacking various methodological ideas implicit in Pinker's
and others' work that suggest than an evolutionary or any other historical
explanation of a behavior's origin is necessary for psychological understanding,
observing, for example, that we figured out the function of the ear and the hand
long before we had an understanding of evolution.
True enough. However, Fodor spends more time arguing that an evolutionary
explanation is not the only possible one than he does arguing that it is in fact
the wrong one, and what time he does spend on that is mostly directed not at the
explanations for sexual differences and similar behaviors at the heart of
evolutionary psychology but at the idea that naturally selected adaptations are
the basis for the cognitive architecture of the mind. Fodor's argument on this
point is tied up to his general argument - which forms the bulk of this book --
that Pinker is wrong in stating we understand the mind's cognitive architecture,
and that it is essentially computational, a model Fodor praises but finds
inadequate for anything like a complete explanation of human reasoning. Fodor is
almost certainly right about this; on these points, Pinker's book is best read
as the sort of 'glass if half full' testimonial new explanatory constructs
sometimes stimulate even when the glass is still mostly empty.
But it is the evolutionary explanations for sexual differences and some
other behaviors more directly tied to our emotions (and biology) that have been
so compelling. What Fodor has to say here is more directly stated in his initial
review of the How the Mind Works in the London Review of Books (1998), and it
seems to consist mostly of a complaint that we just don't need the evolutionary
explanation to understand why men want beautiful women or parents love their
children. Fodor thinks those behaviors can be (obviously are, to his mind) just
for their own sake, and don't need any further explanation as adaptations; that,
while the brain as a whole evolved under natural selection, these and other
particular behaviors, though admittedly innate, need not have arisen because of
the claimed evolutionary benefit. He observes that there could be other unknown
explanations that fit the data, and that we know too little about the specific
evolution of the brain to make as conclusive a connection between, for example,
evolutionary changes in the brain and the desire for beautiful (and hence more
likely fertile) women as we can make between the gradual increase in the length
of the giraffe's neck and the benefit it provides in picking fruit from the tops
of trees.
Fodor is of course correct about the possibility of alternative
explanations and the relative weakness of this data compared to that supporting
anatomical evolution. It's certainly the case that some reasoning in
evolutionary psychology consists of little more than the assertion that a
behavior must both be innate and a result of natural selection because an all
too easily constructed story can be offered for some reproductive benefit. But
Fodor grants that some of these evolutionary explanations are very compelling,
and he offers no specific alternatives other than the conviction that the
behaviors in question probably exist for their own sake and not in the interest
of reproductive success. It's hard not to read him as seizing on the weakness of
some evolutionary explanations and assumptions to exaggerate an across-the-board
likelihood of possible but unknown alternatives, and to then conclude with an
emotional rejection of psychological Darwinism as "preposterous."
The reality is that there is a growing consensus that the evolutionary
explanation is probably right for explaining certain key gender differences in
sexuality and some other behaviors (e.g., love of one's children) with a very
likely biological component. Pinker and others have posed evolutionary
explanations for a great many other behaviors and problems -- Fodor's review
ridicules the idea that a chapter in Pinker's book is actually entitled "The
Meaning of Life" (more on that later) -- and certainly the case has yet to be
made for most of these (for a discussion of some of Pinker's excesses see the
review of How the Mind Works by Jones, 1997). But where there is at least a
likely case for a biological basis, these evolutionary explanations have brought
renewed attention to the 'nature' part of the nature-nurture question and offer
a likely rationale. Such explanations are sometimes compelling enough to
themselves provide some additional support for this biological basis, since
having a good explanation makes it more appealing to interpret sometimes
ambiguous data in a way that fits that explanation (though, following Fodor, it
should be remembered that a plausible evolutionary story is not sufficient for
proving the existence of a biological disposition when it is the only 'evidence'
for that disposition).
Coupled with the seemingly deep-rooted nature of the survival advantage
implied by evolutionary explanation, this biological basis is often seen as
implying it is as futile to ignore these biological urges as it is to ignore
hunger and thirst; that satisfying these behaviors is tied to our happiness; and
that, because such behaviors are both natural and designed for our survival,
they are to some degree justifiable, and perhaps even desirable. When the
behaviors in question include adultery or jettisoning an older wife for a
younger one, it's not hard to wonder at the appeal of these explanations for
some and the furor they provoke in others. Most popular exponents of
evolutionary psychology, including Pinker and particularly Robert Wright before
him (1994), are quick to deny such provocative implications. They and others
have observed that a biological basis (of whatever origin) does not imply that
everyone will have that behavior, or that it will necessarily make someone
happy, or that it is moral. Genes are shaped by evolution for survival into the
next generation, and not for the long-term happiness of their host or the
rightness of the behavior. A genetic grounding for intense male promiscuity
might be good for the genes but bad for the person.
But such rejoinders smack of a too quick political correctness, and it's as
easy to make too little of the data as it is too much. More research will be
needed to clarify just what biological and evolutionary explanations can tell us
about understanding and modifying human behavior. Meanwhile, here's a minimal
likely set of ideas that we can start to use on the probable assumption that
future research will confirm them:
1. A biological basis implies behavior that is at least partly unwilled. This
means that, while these behaviors are not automatically caused by such
inclinations, they are also not entirely a matter of an individual's simple
conscious choice (perhaps even the choice of a male to commit adultery), level
of maturity (often cited as a reason for a male's lack of interest in long-term
commitment) or susceptibility to cultural influences such as advertising
(sometimes cited to explain a male's interest in nubile young women). One's
ability to resist or modify such inclinations, while clearly possible, is
variable, and probably not without costs. In the case of behaviors due mostly or
entirely to cultural factors or individual choice, the difficulty of resisting
or changing the behavior is at least unknown; while deep-rooted habits or
cultural changes can be presumed to have some of the same 'hard-wired'
physiological accompaniments that may make them resistant to change, other such
behaviors may not. A biologically based behavior, on the other hand, can be
assumed to have physiological (e.g., hormonal) underpinnings that can't be
trivially dispensed with. Celibacy, for example, may exist, but we have the
lingering suspicion that fairly unusual and dramatic environmental forces must
be at work to overcome the biologically based opposite inclinations, and such
inclinations might continue even if they are successfully ignored. In truth, we
really don't understand just how malleable different biologically based
behaviors are, or at what cost. Our ignorance on this point is probably the
single most significant constraint on our ability to draw more extensive
implications from the biological basis for these behaviors.
2. A biological basis for a behavior indicates that engaging in the behavior
will produce at least short-term pleasure, and abstaining from it or resisting
it will probably cause some amount of discomfort. Indeed, we regard the
inability to enjoy biologically based pleasures such as sex and food as a
possible sign of pathology in a way that we don't accord more culturally
determined pleasures. While it's true that there's no guarantee that such a
behavior will be good for our long-term happiness, it is at least an open
question to what degree a given individual may weigh such short-term pleasures
in trying to live one's particular life.
3. The great likelihood of innate biological differences in sexual behavior
between men and women undercuts any utopian fantasy of a perfect mating of men
and women. Rather, differences and some amount of resulting conflict would seem
to be built-in. (An equally powerful idea from evolutionary theory is that there
is some inherent conflict between the interests of any one child and those of
the parents, with the former looking to exploit whatever parental resources it
can for its own survival vs. the direct interest of the parents or the parents'
other progeny.)
Pop culture captures the idea perfectly in the recent low-brow comedy
There's Something about Mary (1998), in which Ted is advised by his friend, the
slightly deranged Woogy, to masturbate just before going out on a date with the
coveted Mary (actually, Woogy is shocked to find that Paul has not already
availed himself of this piece of obvious conventional dating wisdom). Woogy's
explanation is that this will not only make Ted less nervous but also make him
more honest and more appealing to women since, for at least a little while, he
will be "thinking like a girl." It's over-simplified (to say the least) and
ignores the possibility of Mary having an active sexual interest herself. But it
gets the evolutionary proposition basically right and draws attention to the
impact of male sexuality, its transforming diminution in the period following
gratification and the interesting prospect of what relations between the sexes
would be like if that period existed forever.
4. Saying that a behavior has a biological basis indeed says nothing about
whether the behavior is moral or immoral. Both evolutionary psychologists and
ethicists alike agree that moral obligation exists in a separate realm, apart
from what might happen to be the case of biology. Evolution is blind to any real
purpose or design; what persists from an evolutionary viewpoint is simply that
which has a reproductive advantage (and the side effects of such factors).
However, the very existence of moral behavior seems to be one more piece of
partly hardwired behavior that has arisen in humans because of its net survival
advantage (for a discussion of the evolutionary origins of morality see Wright
1994, Pinker, 1997, or Katz, 2000). In this view there is no objective truth of
religion or rationality that compels us to behavior morally. The abstract
feeling of 'ought', of having to do the 'right' thing is just one more
intuition, as is our indignation over the wrong-doings of others, or the sense
(suitably molded by the environment) of what is the 'right' behavior in a
specific situation, whether it is keeping a promise or helping someone in need.
Each competing but ultimately inadequate theory of morality might be seen as
primarily based on one 'moral' intuition shaped by evolution and with its own
reproductive advantage and sphere of application, but also possibly in conflict
with another in certain situations, as the messy details of natural selection
often are. Thus, evolution may have formed the utilitarian impulse to act so as
to produce the greatest total happiness, but it also likely produced the
sometimes conflicting Kantian sense of justice, of doing right for right's sake
and not because of the results. Neither pure utilitarianism nor a pure Kantian
ethics will produce the greatest net reproductive benefits, and there isn't any
particular set of axioms to reason the conflict between them.
Belief in a completely rational and well-founded moral code is also
weakened by an evolutionary-based analysis of the concept of free will that is
central to our practical conception of morality. Like morality itself, it is
real enough - the idea that we choose what to do and could have chosen otherwise
is a regular part of our daily experience. But an abundant philosophical
literature on the subject makes clear that it is hard to reconcile the apparent
reality of free will with the well founded materialist view that our actions are
all physically caused and ultimately derived from biological and environmental
antecedents, all of which end up physically encoded in our bodies and brains.
Viewed from the evolutionary perspective, 'free will' is in some sense an
illusion, and may be another evolutionary adaptation that has proven valuable --
useful for running our lives or assigning autonomous responsibility to
individuals when that is a useful approach, e.g., to deter other behaviors [1].
Just as reductionist explanations of free will or other phenomena don't
eliminate their psychological reality, the lack of an absolute basis for
morality does not mean that the choices that are the subject of moral discourse
are unimportant. Todd Andrews, the eccentric central character of John Barth's
The Floating Opera (1988), described by Barth as a "nihilist comedy"(p. vii),
concludes his hyper-rational inquiries into living with the insight that the
lack of absolutes gives him as little reason to commit suicide as not. Todd
realizes (with sincere surprise) that "in the real absence of absolutes, values
less than absolute mightn't be regarded as in no way inferior and even be lived
by" (pp. 251-252) [2]. In other words, our values persist, even though lack of
an absolute basis for them tempers our moral judgments with the knowledge that
they are at root arbitrary and the result of our genetic and environmental
history. We may choose, for example, to accept some adulterous relationships, or
to forego them because we reject violating an explicit commitment or because we
value the intimacy of a relationship that deception or possible exposure might
threaten. Any of these positions may turn out to be most consonant with our
other values and choices, and for any them we must acknowledge a somewhat
arbitrary quality to our choice and the possibility that others might choose
differently. We do this, though, without giving up the importance of the
particular choice for us. We can also maintain our belief that some particular
others might be best served by the same choice, or perhaps just our own interest
in being surrounded by such people, and hence the importance of persuading them
to think similarly.
This is consistent with the post-modern view that denotes no special status
to moral principles, though it is more of a multi-moralism -- with multiple
equally valid (in the evolutionary sense) moral impulses and intuitions binding
all people to varying degrees - than a moral relativism that allows for any
arbitrary moral intuition. Once again, a piece of pop culture captures the
current evolutionary position. The TV show Seinfeld is the exaggerated, comical
embodiment of both the underlying nihilism of this position and the possibility
of relative value - self-absorbed, mostly amoral characters who openly wonder
what anything is about besides the next sexual relationship, but who also
demonstrate the existence of relative values such as friendship, the correct way
to break up with someone (phone call or in person, depending on the length of
the relationship) and the choice of simple pleasures such as cereal for
breakfast or watching baseball on TV.
5. While evolutionary psychology may help resolve certain philosophical
problems such as free will and the basis of morality, it doesn't provide any
answer to fundamental questions about the meaning of life, and Pinker does not
claim it does, his chapter title on the subject notwithstanding. However, Pinker
is correct in observing that evolutionary psychology suggests that some of these
fundamental questions may not be answerable at all. The key insight here is that
any life form is at any given time at some arbitrary stage of evolutionary
development. Fodor stated it well, several years ago: We would not expect
spiders to be able to understand the "true science," and it's therefore
reasonable to assume there are at least some limits on what our own minds can
grasp, minds which, to the extent they are the product of natural selection,
would have evolved for the mostly mundane tasks most important to our own
survival (Fodor, 1983, p. 126).
At least two problems suggest themselves as unsolvable. The first,
discussed by Pinker and others, is a problem familiar to readers of this
journal: the 'mind' part of the mind-body problem, the "hard problem" of
consciousness: just how it is that our physical brains produce the feelings and
sensations of consciousness, our particular sensations of smell, color and so on
(Chalmers, 1995). Wittgenstein said it best: "The feeling of an unbridgeable
gulf between consciousness and brain process.... This idea of a difference in
kind is accompanied by slight giddiness..." (1953, p. 124). To this reader,
neither Wittgenstein's analysis of the difficulty - linguistic confusion - nor
the many attempts since then have much headway, leaving Colin McGinn's tentative
verdict of unsolvability based on evolutionary-based limitations as the most
reasonable position (McGinn, 1989).
The second likely unsolvable problem is the big (biggest?) question of why
anything exists - the problem of the origin of the universe, in the broadest
sense. The problem is a familiar one, but so ill-suited to modern scientific
inquiry that it is today mostly ignored by science, and Pinker and others
working in this area have also ignored it [4]. Big Bang theory may explain the
moment of the universe's creation, but not why the laws it depends on exist -
not why there should be anything at all (a pre-Big Bang state, or the physical
laws that let it come into being, if you prefer) [3]. New advances in cosmology
tease with the prospect of gaining on this underlying problem but in fact leave
it untouched, since whatever can possibly be offered by way of explanation
immediately becomes part of what now must be explained. This is a difficulty
that seems to derive from the very way our minds evolved to think about
causation and explanation, which evolution has presumably made more suited to
visible, mechanistic instances of cause and effect. Those insisting on an answer
are (as with the hard problem of consciousness) forced into one of several
unsatisfactory positions - ignoring the problem, declaring it already solved or
meaningless (when most people can readily feel the irrational awe it inspires),
or entrusting it to religion, which tries to answer it by substituting another
equally unknowable mystery - God -- in its place.5
Naturally, there's been speculation that the widespread tendency towards
religious belief is itself an evolutionary adaptation, e.g., perhaps those with
the first religious inclinations may have been more likely to sacrifice
themselves for the good of the group, and so help perpetuate the genes of the
group which overlapped their own genes (Edward Wilson, for one, suggests this in
Consilience: The Unity of Knowledge, 1998, p. 258, though evolutionary theories
of "group selection" that rely on individual sacrifice are controversial). Even
for those not religious, it seems that human nature may contain an inclination
for some central value or passion that makes life as meaningful and worthwhile
as it can be, and, as with religion, makes us more likely to carry on our own
genetic heritage (or perhaps just makes us more sexually attractive, as
suggested by the work of Miller, 1998). This passion might be morally correct
behavior, artistic expression, the pursuit of scientific knowledge or the
primacy of human relationships - or the expression of our individual will and
intellect on a world we consider fundamentally without any intelligible meaning
or value.
Whatever our passion, it is, like our free will and chosen values, both
real in our experience and, from a third person point of view, a somewhat
arbitrary artifact of evolution and our particular environmental history. It may
be the essence of understanding our evolutionary heritage that we live the
paradox of embracing and experiencing as most important to us what we can
understand to be without any absolute foundation or explanation (Wittgenstein
concludes his deconstruction of metaphysics in the Tractatus (1961) by observing
that ethics, aesthetics and pretty much everything of value is "transcendental"
and outside our ability to say anything sensible about it). The lack of such
foundation is, as Robert Wright has observed, similar to the existentialist's
views of the world as fundamentally absurd. But where existentialism cannot lay
claim to any value - yet nevertheless trumpets the primacy and intrinsic value
of autonomous choice - evolutionary psychology helps explain the basis for all
sorts of pleasures and (relative) values, as well as providing the realization
that who we are and what we do may not be as freely chosen as we think.
NOTES
1. This is a form of the "compatibilist" position: accepting a certain
determinism with regard to our behavior but also accepting a compatible reality
and usefulness to the concept of free will. See Dennett (1984) for a fuller
account, or Libet (1999) for recent discussions on the subject.
2. This 1988 version, the same as the 1967 revised edition, is the author's
original text. As Barth explains in the preface to the 1988 version, the first
publication of the work in 1956 contained a publisher-demanded change to make
the ending less nihilistic (and more explicit about relative values), with the
love of a child being the key reason Todd aborts his plan to commit suicide.
3. For an effort in trying to extend Fodor's and McGinn's thinking on the limits
of understanding to the problem of the origin of the universe see Krellenstein
(1995). Pinker also includes in his list of unsolvable problems several problems
-- morality, free will, meaning, etc. - which, as partly explained above, seem
more likely to be resolved by evolutionary thinking.
4. Stephen Hawking (1988) has posed the problem this way: "Even if there is only
one unified theory, it is just a set of rules and equations. What is it that
breathes fire into the equations and makes a universe for them to describe? The
usual approach of science of constructing a mathematical model cannot answer the
questions of why there should be a universe for the model to describe. Why does
the universe go to all the bother of existing?" (p. 174).
5Commenting on those who, seeing the difficulty, declare the problem
meaningless, Robert Nozick (1981) has asked "why do they cheerfully reject the
question rather than despairingly observe that it demarcates a limit of what we
can hope to understand?" (p. 115).
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